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lightbulbs

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Senior | Next Rank: 100 Posts
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by success1111 » Wed May 13, 2009 8:36 am
string of 10 lightbulbs is wired in such a way that if
any individual lightbulb fails, the entire string fails. If for
each individual lightbulb the probability of failing during
time period T id 0.06, what is the probability that the
string of lightbulbs will fail during time period T?

A.0.06
B.(0.06)^10
C.1-(0.06)^10
D.(0.94)^10
E.1-(0.94)^10
Trust but verify.
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Re: lightbulbs

by Vemuri » Wed May 13, 2009 8:43 am
success1111 wrote:string of 10 lightbulbs is wired in such a way that if
any individual lightbulb fails, the entire string fails. If for
each individual lightbulb the probability of failing during
time period T id 0.06, what is the probability that the
string of lightbulbs will fail during time period T?

A.0.06
B.(0.06)^10
C.1-(0.06)^10
D.(0.94)^10
E.1-(0.94)^10
IMO B
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by scoobydooby » Wed May 13, 2009 8:54 am
would go for E

for the string to succeed, each of the 10 bulbs would have to be successful.

prob of success of each bulb:1-0.6=0.94
prob of success of each of 10 bulbs: 0.94^10

prob(string fails)=1-(prob string succeeds)
=1-(0.94)^10
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by m&m » Wed May 13, 2009 9:04 am
would also go for E

1-probability that they all work

prob of working for each bulb is 1-0.06 = 0.94

so 1-(0.94)^10 --> E
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by success1111 » Wed May 13, 2009 9:21 am
m&m wrote:would also go for E

1-probability that they all work

prob of working for each bulb is 1-0.06 = 0.94

so 1-(0.94)^10 --> E
OA is E. Thanks
Trust but verify.
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